A few years later saw the astronomic revolution. Ancient thought, after long deliberation, had decided to enclose the universe in a confined system, with established limits. Copernicus took no notice of these limits, and launched out in thought into the infinite. The impression produced on the men of the sixteenth century by these two great events was profound. The bold spirits who had dared to cross the two limits considered insuperable on earth and in the sky had come back with a rich booty of land and stars. Was the world then greater and man more powerful than the ancients had thought, and had the ancients been wrong in seeking to limit the efforts of human genius so strictly? Gradually, during the seventeenth and eighteenth centuries, the effort of the human spirit to free itself from the ancient limits continued, increased, and became bolder and more methodical. Subtle and ingenious philosophies delivered masked but clear attacks on the limits which marked the bounds of Good and Evil, Truth and Error; on tradition, on century-old institutions, on authority in all its forms. They pretended to wish to ascertain whether the limits were solidly planted in the right place; but in reality they undermined their foundations. Little by little an idea crept into men’s minds, an idea which was the negation of all the limits within which the world had lived until then; an idea which was bound to upset the conception of social and moral life; the idea of liberty, applied to religion, culture, and politics. At the same time, by means of science and fire, man sought very timidly, if not to free himself from, at least to enlarge, the limits which nature seemed to have set to his forces. The strata of coal began to be discovered and exploited. Men set themselves to invent machines more complicated and more rapid than those of which their fathers made use; the steam-engine, the fountainhead of all the formidable agitation which has invaded the world, made its appearance; the great era of iron and of fire began. And lo! finally a formidable cataclysm, of which man had never seen the like in a few years, upset traditions, and wrought havoc amongst states, institutions, and old-established laws. To the strains of the _Marseillaise_, on the ruins of the Bastile, on the fields of Marengo and Austerlitz, the work sketched out by Columbus and Copernicus, continued by Galileo, Descartes, Voltaire, Rousseau, and Kant, was completed. Man arose, tore up, and overturned all the ancient limits and planted the new ones with his own hands, at his own good pleasure, not only for himself but also for the authorities of Heaven and earth, who had until then imposed their limits upon him.